RIVA128ZX Datasheet, PDF (58/85 Pages) STMicroelectronics – 128-BIT 3D MULTIMEDIA ACCELERATOR

RIVA128ZX
128-BIT 3D MULTIMEDIA ACCELERATOR
mode pixel format, the least significant bits of each color are located separately in the top byte of the pixel.
This also permits an 8:8:8 mode without gamma with <1% error if desired.
Use of pixel input pins (FBD[31:0])
Pixel 0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 X X XX X X X
Red gamma
Green gamma
Blue gamma
1 X R1 R0 G1 G0 B1 B0 R9 R8 R7 R6 R5 R4 R3 R2 G9 G8 G7 G6 G5 G4 G3 G2 B9 B8 B7 B6 B5 B4 B3 B2
NOTE
This 32-bit representation can be extended to 64-bit and 128-bit widths by duplicating the 32-bit word in little-endian format.
Limitations on line lengths
Table 19. Permitted line length multiples
bpp
Number of pixels that the line
length must be a multiple of
8 16 32
421
11.3 HARDWARE CURSOR
The RIVA128ZX supports a 32x32 15bpp full color
hardware cursor as defined by Microsoft Win-
dows.
• Full color 5:5:5 format
• Pixel complement
• Transparency
• Pixel inversion
The cursor pattern is stored in a 2KByte bitmap lo-
cated in off-screen framestore. Details of program-
ming the hardware cursor are given in the
RIVA128ZX Programming Reference Manual [2].
Registers control cursor enabling/disabling, loca-
tion of cursor bitmap and cursor display coordi-
nates. The cursor data and it’s position should only
be changed during frame flyback. The cursor
should be disabled when not being used.
Cursor format
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
A
Red
Green
Blue
The 5-bit RGB color components are expanded to
10 bits per color before combining with the graph-
ics display data. The expanded 10-bit color is com-
posed of the 5-bit cursor color replicated in the up-
per and lower 5-bit fields. The cursor pixels are
combined such that the cursor will overlay a video
window if present.
Cursor pixel bit 15 (A) is the replace mode bit.
When A=1, the cursor pixel replaces the normal
display pixel. If A=0, the expanded 30 bits of the
cursor color are XORed with the display pixel to
provide the complement of the background color.
Cursor pixels can be made transparent (normal
display pixel is unmodified) by setting to a value of
0x0000. To invert the bits of the normal display
pixel, the cursor pixel should be set to 0x7FFF.
58/85